TY - JOUR
T1 - Development of an electrochemical insulin sensor based on the insulin-linked polymorphic region
AU - Gerasimov, Jennifer Y.
AU - Schaefer, Cody S.
AU - Yang, Weiwei
AU - Grout, Rebecca L.
AU - Lai, Rebecca Y.
N1 - Funding Information:
The authors acknowledge NSF REU ( DMR-0851703 ), NSF Career ( CHE-0955439 ), and Army Research Office ( W911NF-09-2-0039 ) for financial support.
PY - 2013/4/5
Y1 - 2013/4/5
N2 - Here we report the design and fabrication of an electrochemical aptamer-based (E-AB) sensor for detection of insulin. The aptamer used in this study is the insulin-linked polymorphic region (ILPR) sequence, a G-rich sequence that presumably undergoes ligand-induced folding to form a G-quadruplex in presence of insulin. Our circular dichroism data, however, suggests that the ILPR sequence, even in absence of the target, is predominantly in a G-quadruplex-like form. Insulin binding, however, has shown to further induce the formation of the G-quadruplex. To evaluate the potential of the ILPR sequence as a biosensing element, we constructed two E-AB insulin sensors that are identical in all aspects but the location of the methylene blue (MB) redox label. We find that the sensor fabricated with internal MB-modified probes (In-IT) shows enhanced sensing behavior when compared to one fabricated using terminal-MB modified probes (In1). The improvements observed with the In-IT sensor could be attributed to the more effective obstruction of electron transfer upon insulin binding. Overall, both sensors perform well, affording a detection limit of 10 nM and 50 nM for the In-IT and In1 sensors, respectively.
AB - Here we report the design and fabrication of an electrochemical aptamer-based (E-AB) sensor for detection of insulin. The aptamer used in this study is the insulin-linked polymorphic region (ILPR) sequence, a G-rich sequence that presumably undergoes ligand-induced folding to form a G-quadruplex in presence of insulin. Our circular dichroism data, however, suggests that the ILPR sequence, even in absence of the target, is predominantly in a G-quadruplex-like form. Insulin binding, however, has shown to further induce the formation of the G-quadruplex. To evaluate the potential of the ILPR sequence as a biosensing element, we constructed two E-AB insulin sensors that are identical in all aspects but the location of the methylene blue (MB) redox label. We find that the sensor fabricated with internal MB-modified probes (In-IT) shows enhanced sensing behavior when compared to one fabricated using terminal-MB modified probes (In1). The improvements observed with the In-IT sensor could be attributed to the more effective obstruction of electron transfer upon insulin binding. Overall, both sensors perform well, affording a detection limit of 10 nM and 50 nM for the In-IT and In1 sensors, respectively.
KW - Circular dichroism
KW - Electrochemical
KW - Insulin
KW - Insulin-linked polymorphic region
KW - Methylene blue
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U2 - 10.1016/j.bios.2012.10.046
DO - 10.1016/j.bios.2012.10.046
M3 - Article
C2 - 23202332
AN - SCOPUS:84871661808
SN - 0956-5663
VL - 42
SP - 62
EP - 68
JO - Biosensors and Bioelectronics
JF - Biosensors and Bioelectronics
IS - 1
ER -